Comparing tuberculin skin test and interferon γ release assay (T-SPOT.TB) to diagnose latent tuberculosis infection in household contacts.
- Author:
Hyun Woo LEE
1
;
Yeon Joo LEE
;
Se Joong KIM
;
Jong Sun PARK
;
Young Jae CHO
;
Ho Il YOON
;
Choon Taek LEE
;
Jae Ho LEE
Author Information
- Publication Type:Original Article
- Keywords: Latent tuberculosis; Tuberculin test; Interferon-gamma release tests
- MeSH: Bacillus; Diagnosis; Family Characteristics*; Humans; Interferon-gamma Release Tests; Interferons*; Latent Tuberculosis*; Mycobacterium bovis; Prevalence; Skin Tests*; Skin*; Spouses; Sputum; Thorax; Tuberculin Test; Tuberculin*; Vaccination
- From:The Korean Journal of Internal Medicine 2017;32(3):486-496
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND/AIMS: The tuberculin skin test (TST) and interferon γ release assay are currently used as diagnostic tools to detect latent tuberculosis (TB) infection; however, there are inconsistencies about the degree of agreement between the tests. We aimed to evaluate the concordance rate between the two tests in household contacts of a country with intermediate TB burden, where most people were vaccinated. METHODS: We recruited household contacts who spent > 8 hours daily with patients with microbiologically confirmed active pulmonary TB, and received both TST and T-SPOT.TB (Oxford Immunotec) simultaneously. The degree of agreement was analysed according to TST cutoff and Bacille Calmette-Guerin (BCG) vaccination status. Relevant factors were analysed to establish the association with TST or T-SPOT.TB. RESULTS: Among 298 household contacts, 122 (40.9%) were spouses, and 250 (83.9%) had received BCG vaccination. In the contact sources, 117 (39.3%) showed a positive result for acid-fast bacillus (AFB) sputum smear and 109 (36.6%) had cavities. The highest agreement rate of 69.5% and κ value of 0.378 were found with a 10 mm cutoff. Spouse, time interval from TB diagnosis to test, and AFB sputum smear positivity were significantly associated with a positive result for T-SPOT.TB. Sex, BCG vaccination, and cavity on chest computed tomography were related to TST positivity. CONCLUSIONS: The present study suggested it was not possible for TST and T-SPOT.TB to replace each other because of considerable discrepancy between the two tests in household contacts in a country with intermediate TB prevalence.
